Mixing apparatus



Dec. 29, 1942.

E. KROPP MIXING APPARATUS Filed Oct. 28, 1940 mw m 0 A M r mi 5 PatentedDec. 29, 1942 MIXING APPARATUS Einar Krupp, Cleveland, Ohio, assignor toThe Standard Oil Company, Cleveland, Ohio, a corporation of Ohio-Application October 28, 1940, Serial No. 363,079

Claims. (01

In the mixing of materials it is particularly desired to attain ahomogeneity of the admixed materials quickly and with a minimumapplication of power; and where the materials mixed are of dissimilarcharacter a particular desideratum is to attain homogeneity withoutundue introduction of extraneous air to cause foaming and froth whereliquid is involved. In accordance with the present invention, dissimilarcomponents may be mixed thoroughly and quickly, and where one componentis for instance a liquid and anotheris a powder or finely divided solid,undue lumping and segregation, as well as foaming, may be avoided, Whileattaining the desired dispersion or homogeneity of mixture.

To the accomplishment of the foregoing and related ends, the invention,then, comprises the features hereinafter fully described, andparticularly pointed out in the claims, the following description andthe annexed drawing setting forth in detail certain illustrativeembodiments of the invention, these being indicative however, of but afew of the various ways in which the principle of the invention may beemployed.

In said annexed drawing- Fig. 1 is a vertical elevation, partly insection, showing an embodiment of the invention; and Fig. 2 is afragmentary similar view of a modification. 1

The invention may be best understood by reference to a particular forminvolving the mixing of pulverized coal in water to form a homogeneousslurry adapted to be forwarded through pipe line transportation systems.A mixing tank or container 2 for such purpose is provided with a mixinghopper II which has a conically tapering inlet section 3 leading to anarrow throat A whence a shorter diverging section 5 opens into thetank. In relationship, a form of Venturi effeet is initially provided.Axially directed into the throat portion and slightly spaced backtherefrom is a feed jet I having a choked or constricted nozzle outlet8. By this, and by the converging shape of the hopper leading to thethroat, an acceleration velocity of materials proceeding down in thehopper to the throat is attained. Another feed inlet is providedlaterally near the wall of the hopper, as an inlet iii. Positioned in azone intermediate between this latter and the wall of the hopper is afurther feed inlet I2 which, as shown more particularly in Fig. 1, maytake the form of a circular distributing nozzle 53 extending entirelyaround within the wall of the hopper, but spaced therefrom to allowin-flow of liquid as over-flowing from the tank into the hopper underthe propulsive action of the axial jet. Feeding powdered coal throughthe inlet l0 and water through the axial inlet 1, the propulsive jettingof the water at high velocity through the nozzle 8 introduces adifferential of velocity into the mass above the throat of the hopper,and forwards it through the throat, while the powdered coalprogressively comes down from the feed inlet!!! and a wall of liquid intwo layers is supplied from the annular feed inlet 53 and the in-fiow ofliquid entering from the tank over the upper edge of the hopper. Aslurry stabilizing agent, for instance such as disclosed in patent to R.E. Burk No. 2,128,913 may be included in one or both liquid feeds, ifdesired.

The highest velocity is at the center of the throat 4 and in progressivezones to the bounding wall virtual thin layers in differential velocityare in effect rubbed into each other and thence in turbulent or thoroughintermixture at the diverging section 5, it being noticed however thatsuch turbulence is in a region below the converged sealing-01f mass ofcoal so that air is not drawn in to cause deleterious foaming. With thedivergence of the outlet section there is a sufiicient lessened pressureto bring about rapid lateral in-fiow and commingling from thesurrounding liquid in the tank, and thereby particularly rapidhomogeneous mixing of the entire mass.

Similarly, other powders and liquids may be brought into slurry form,and components also not precisely of such categories, but any substanceswhich are capable of being fed and commingled in this manner. With somematerials the liquid feed at the wall of the hopper can be omitted.

In some cases, instead of an annular feedhead l3 for liquid, the supplymay be provided by a plurality of spaced pipes or nozzles; or wheresuificient, one such feed pipe or nozzle may be applied.

As a further refinement, the feed inlet, such as at 2, Fig. 2, maydesirably have its discharge directed angularly to form a whirling layereffeet while being downwardly directed into the converging mixingthroat. For some materials, the upper edge of the hopper 3 instead ofbeing slightly submerged below the level of the liquid in the tank orcontainer 2 such as to receive a constant over-flow therefrom, maybeelevated slightly above the level of liquid in the tank, and therebymaterials which inherently foam or involve components which are prone toaccumulate at the top, can thus be selectively skimmed oft into thevortex of the mixing hopper, without bringing in large amounts of liquidbody proper.

Other modes of applying the principle of the invention may be employed,change being made as regards the details described, provided thefeatures stated in any of the following claims, or the equivalent ofsuch, be employed.

I therefore particularly point out and distinctly claim as my invention:

1. A mixing apparatus, comprising a container, a hopper therein with itsupper edge at a level to receive liquid over-flow circulating from thecontainer and having a conically tapering inlet section leading to anarrow throat and a diverging section leading from the throat into thecontainer, an axial feed jet with a constricted nozzle near the hopperthroat, a feed inlet for pulverulent solid matter near the top of thehopper, and an annular feed inlet for liquid interposed between theperiphery of the hopper and said feed inlet for pulverulent matterintroducing a layer of liquid in flowing direction along the wall of thehopper.

2. A mixing apparatus, comprising a container, a hopper therein abovethe liquid level in the container, said hopper having a conicallytapering inlet section leading to a narrow throat and a divergingsection leading from the throat into the container, an axial feed jetwith a constricted nozzle near the hopper throat, a feed inlet forpulverulent solid matter near the top of the hopper, and an annular feedinlet for liquid on the slope of the hopper interposed between theperiphery of the hopper and said feed inlet for pulvrulent matterintroducing a layer of liquid in flowing direction along the Wall of thehopper.

3. A mixing apparatus, comprising a container,

a hopper therein having a conically tapering inlet section leading to anarrow throat and a diverging section leading from the throat into thecontainer, an axial feed jet with a constricted nozzle near the hopperthroat, a feed inlet for pulverulent solid matter near the top of thehopper, and an annular feed inlet for liquid on the slope of the hopperinterposed between the periphery of the hopper and said feed inlet forpulverulent matter introducing a layer of liquid in flowing directionalong the wall of the hopper.

4. A mixing apparatus, comprising a container, a hopper therein having aconically tapering inlet section leading to a narrow throat and adiverging section leading from the throat into the container, an axialfeed jet with a constricted nozzle near the hopper throat, a feed inletfor pulverulent solid matter near the top of the hopper, and an annularfeed inlet for liquid on the slope of the hopper interposed between theperiphery of the hopper and said feed inlet for pulverulent matterintroducing liquid along the wall of the hopper.

5. A mixing apparatus, comprising a container, a hopper therein having aconically tapering inlet section leading to a narrow throat and adiverging section leading from the throat into the container, an axialfeed jet with a constricted nozzle near the hopper throat, a feed inletfor pulverulent solid matter near the top of the hopper, and anotherfeed inlet for liquid on the slope of the hopper interposed between saidfeed inlet for pulverulent matter introducing liquid along the Wall ofthe hopper.

EINAR KROPP.

